Just to clarify, you can't load the trainer in Aurora?
Are you using a 32 bit OS? Some games install according to the type (ie 32 vs 64) of OS you have.
If you are already using a 64 bit OS, then the issue might be due to the game having been updated since the last trainer was put out. Steam indicates that there was an update for the game on 7 June. In which case, you will have to request an update for the trainer.
Please use the update notification system to report a game patch, update or to report that the trainer may not be working with the latest version of the game. If 3 or more reports have been filed, consider BOOSTING the priority of this title for a faster turnaround on the updated trainer.
Please use the trainer option request system for requesting new options be added to this trainer and/or vote on options already requested.